/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.support;

import java.util.function.Supplier;

import org.springframework.beans.factory.config.BeanDefinitionCustomizer;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;

/**
 * Programmatic means of constructing
 * {@link org.springframework.beans.factory.config.BeanDefinition BeanDefinitions}
 * using the builder pattern. Intended primarily for use when implementing Spring 2.0
 * {@link org.springframework.beans.factory.xml.NamespaceHandler NamespaceHandlers}.
 *
 * @author Rod Johnson
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 2.0
 */
public class BeanDefinitionBuilder {

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link GenericBeanDefinition}.
     */
    public static BeanDefinitionBuilder genericBeanDefinition() {
        return new BeanDefinitionBuilder(new GenericBeanDefinition());
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link GenericBeanDefinition}.
     *
     * @param beanClassName the class name for the bean that the definition is being created for
     */
    public static BeanDefinitionBuilder genericBeanDefinition(String beanClassName) {
        BeanDefinitionBuilder builder = new BeanDefinitionBuilder(new GenericBeanDefinition());
        builder.beanDefinition.setBeanClassName(beanClassName);
        return builder;
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link GenericBeanDefinition}.
     *
     * @param beanClass the {@code Class} of the bean that the definition is being created for
     */
    public static BeanDefinitionBuilder genericBeanDefinition(Class<?> beanClass) {
        BeanDefinitionBuilder builder = new BeanDefinitionBuilder(new GenericBeanDefinition());
        builder.beanDefinition.setBeanClass(beanClass);
        return builder;
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link GenericBeanDefinition}.
     *
     * @param beanClass        the {@code Class} of the bean that the definition is being created for
     * @param instanceSupplier a callback for creating an instance of the bean
     * @since 5.0
     */
    public static <T> BeanDefinitionBuilder genericBeanDefinition(
            @Nullable Class<T> beanClass, Supplier<T> instanceSupplier) {

        BeanDefinitionBuilder builder = new BeanDefinitionBuilder(new GenericBeanDefinition());
        builder.beanDefinition.setBeanClass(beanClass);
        builder.beanDefinition.setInstanceSupplier(instanceSupplier);
        return builder;
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
     *
     * @param beanClassName the class name for the bean that the definition is being created for
     */
    public static BeanDefinitionBuilder rootBeanDefinition(String beanClassName) {
        return rootBeanDefinition(beanClassName, null);
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
     *
     * @param beanClassName     the class name for the bean that the definition is being created for
     * @param factoryMethodName the name of the method to use to construct the bean instance
     */
    public static BeanDefinitionBuilder rootBeanDefinition(String beanClassName, @Nullable String factoryMethodName) {
        BeanDefinitionBuilder builder = new BeanDefinitionBuilder(new RootBeanDefinition());
        builder.beanDefinition.setBeanClassName(beanClassName);
        builder.beanDefinition.setFactoryMethodName(factoryMethodName);
        return builder;
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
     *
     * @param beanClass the {@code Class} of the bean that the definition is being created for
     */
    public static BeanDefinitionBuilder rootBeanDefinition(Class<?> beanClass) {
        return rootBeanDefinition(beanClass, null);
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
     *
     * @param beanClass         the {@code Class} of the bean that the definition is being created for
     * @param factoryMethodName the name of the method to use to construct the bean instance
     */
    public static BeanDefinitionBuilder rootBeanDefinition(Class<?> beanClass, @Nullable String factoryMethodName) {
        BeanDefinitionBuilder builder = new BeanDefinitionBuilder(new RootBeanDefinition());
        builder.beanDefinition.setBeanClass(beanClass);
        builder.beanDefinition.setFactoryMethodName(factoryMethodName);
        return builder;
    }

    /**
     * Create a new {@code BeanDefinitionBuilder} used to construct a {@link ChildBeanDefinition}.
     *
     * @param parentName the name of the parent bean
     */
    public static BeanDefinitionBuilder childBeanDefinition(String parentName) {
        return new BeanDefinitionBuilder(new ChildBeanDefinition(parentName));
    }


    /**
     * The {@code BeanDefinition} instance we are creating.
     */
    private final AbstractBeanDefinition beanDefinition;

    /**
     * Our current position with respect to constructor args.
     */
    private int constructorArgIndex;


    /**
     * Enforce the use of factory methods.
     */
    private BeanDefinitionBuilder(AbstractBeanDefinition beanDefinition) {
        this.beanDefinition = beanDefinition;
    }

    /**
     * Return the current BeanDefinition object in its raw (unvalidated) form.
     *
     * @see #getBeanDefinition()
     */
    public AbstractBeanDefinition getRawBeanDefinition() {
        return this.beanDefinition;
    }

    /**
     * Validate and return the created BeanDefinition object.
     */
    public AbstractBeanDefinition getBeanDefinition() {
        this.beanDefinition.validate();
        return this.beanDefinition;
    }


    /**
     * Set the name of the parent definition of this bean definition.
     */
    public BeanDefinitionBuilder setParentName(String parentName) {
        this.beanDefinition.setParentName(parentName);
        return this;
    }

    /**
     * Set the name of a static factory method to use for this definition,
     * to be called on this bean's class.
     */
    public BeanDefinitionBuilder setFactoryMethod(String factoryMethod) {
        this.beanDefinition.setFactoryMethodName(factoryMethod);
        return this;
    }

    /**
     * Set the name of a non-static factory method to use for this definition,
     * including the bean name of the factory instance to call the method on.
     *
     * @since 4.3.6
     */
    public BeanDefinitionBuilder setFactoryMethodOnBean(String factoryMethod, String factoryBean) {
        this.beanDefinition.setFactoryMethodName(factoryMethod);
        this.beanDefinition.setFactoryBeanName(factoryBean);
        return this;
    }

    /**
     * Add an indexed constructor arg value. The current index is tracked internally
     * and all additions are at the present point.
     */
    public BeanDefinitionBuilder addConstructorArgValue(@Nullable Object value) {
        this.beanDefinition.getConstructorArgumentValues().addIndexedArgumentValue(
                this.constructorArgIndex++, value);
        return this;
    }

    /**
     * Add a reference to a named bean as a constructor arg.
     *
     * @see #addConstructorArgValue(Object)
     */
    public BeanDefinitionBuilder addConstructorArgReference(String beanName) {
        this.beanDefinition.getConstructorArgumentValues().addIndexedArgumentValue(
                this.constructorArgIndex++, new RuntimeBeanReference(beanName));
        return this;
    }

    /**
     * Add the supplied property value under the given name.
     */
    public BeanDefinitionBuilder addPropertyValue(String name, @Nullable Object value) {
        this.beanDefinition.getPropertyValues().add(name, value);
        return this;
    }

    /**
     * Add a reference to the specified bean name under the property specified.
     *
     * @param name     the name of the property to add the reference to
     * @param beanName the name of the bean being referenced
     */
    public BeanDefinitionBuilder addPropertyReference(String name, String beanName) {
        this.beanDefinition.getPropertyValues().add(name, new RuntimeBeanReference(beanName));
        return this;
    }

    /**
     * Set the init method for this definition.
     */
    public BeanDefinitionBuilder setInitMethodName(@Nullable String methodName) {
        this.beanDefinition.setInitMethodName(methodName);
        return this;
    }

    /**
     * Set the destroy method for this definition.
     */
    public BeanDefinitionBuilder setDestroyMethodName(@Nullable String methodName) {
        this.beanDefinition.setDestroyMethodName(methodName);
        return this;
    }


    /**
     * Set the scope of this definition.
     *
     * @see org.springframework.beans.factory.config.BeanDefinition#SCOPE_SINGLETON
     * @see org.springframework.beans.factory.config.BeanDefinition#SCOPE_PROTOTYPE
     */
    public BeanDefinitionBuilder setScope(@Nullable String scope) {
        this.beanDefinition.setScope(scope);
        return this;
    }

    /**
     * Set whether or not this definition is abstract.
     */
    public BeanDefinitionBuilder setAbstract(boolean flag) {
        this.beanDefinition.setAbstract(flag);
        return this;
    }

    /**
     * Set whether beans for this definition should be lazily initialized or not.
     */
    public BeanDefinitionBuilder setLazyInit(boolean lazy) {
        this.beanDefinition.setLazyInit(lazy);
        return this;
    }

    /**
     * Set the autowire mode for this definition.
     */
    public BeanDefinitionBuilder setAutowireMode(int autowireMode) {
        beanDefinition.setAutowireMode(autowireMode);
        return this;
    }

    /**
     * Set the depency check mode for this definition.
     */
    public BeanDefinitionBuilder setDependencyCheck(int dependencyCheck) {
        beanDefinition.setDependencyCheck(dependencyCheck);
        return this;
    }

    /**
     * Append the specified bean name to the list of beans that this definition
     * depends on.
     */
    public BeanDefinitionBuilder addDependsOn(String beanName) {
        if (this.beanDefinition.getDependsOn() == null) {
            this.beanDefinition.setDependsOn(beanName);
        } else {
            String[] added = ObjectUtils.addObjectToArray(this.beanDefinition.getDependsOn(), beanName);
            this.beanDefinition.setDependsOn(added);
        }
        return this;
    }

    /**
     * Set the role of this definition.
     */
    public BeanDefinitionBuilder setRole(int role) {
        this.beanDefinition.setRole(role);
        return this;
    }

    /**
     * Apply the given customizers to the underlying bean definition.
     *
     * @since 5.0
     */
    public BeanDefinitionBuilder applyCustomizers(BeanDefinitionCustomizer... customizers) {
        for (BeanDefinitionCustomizer customizer : customizers) {
            customizer.customize(beanDefinition);
        }
        return this;
    }

}
